Annotation For Makefile

Origin for each line in Makefile from check-in f74a2e47ab:

0a9369ff13 2019-05-02    1: all: example.so
0a9369ff13 2019-05-02    2: 
e90770a5a7 2019-05-02    3: example.c: $(shell find example -type f) $(shell find lib -type f) xvfs.c.rvt xvfs-create Makefile
0a9369ff13 2019-05-02    4: 	./xvfs-create --directory example --name example > example.c.new
0a9369ff13 2019-05-02    5: 	mv example.c.new example.c
0a9369ff13 2019-05-02    6: 
e90770a5a7 2019-05-02    7: example.o: example.c xvfs-core.h Makefile
f74a2e47ab 2019-05-02    8: 	cc -fPIC -Wall -I. -o example.o -c example.c
e90770a5a7 2019-05-02    9: 
e90770a5a7 2019-05-02   10: example.so: example.o Makefile
f74a2e47ab 2019-05-02   11: 	cc -fPIC -shared -o example.so example.o
e90770a5a7 2019-05-02   12: 
f74a2e47ab 2019-05-02   13: test: example.so
f74a2e47ab 2019-05-02   14: 	echo 'load ./example.so Xvfs_example; puts OK' | tclsh | grep '^OK$$'
0a9369ff13 2019-05-02   15: 
0a9369ff13 2019-05-02   16: clean:
0a9369ff13 2019-05-02   17: 	rm -f example.so example.o example.c
0a9369ff13 2019-05-02   18: 
0a9369ff13 2019-05-02   19: distclean: clean
0a9369ff13 2019-05-02   20: 
0a9369ff13 2019-05-02   21: .PHONY: all clean distclean test